A New Civil War is starting, which gun will you take?

SCENARIO:
Post Civil War 2. The world is in chaos. The government has collapsed. The cities are a wasteland. Supply lines have been cut, and your family has no way to buy food. You need to leave your home, and journey South where you know it is safe. There are many thousands of miles to cover and it is extremely dangerous. You can't trust anybody but yourself.

You can only take 1 gun. Suppose the world's arsenal is available to you. What gun will you take, and why?

12 gauge, semi-auto. With extra slug barrel. OR .17 HMR, accurate, deadly on small game, deadly with game points on larger if you put it in the hole. Also, just as an informative statement that no one cares to hear, I cut the hell out of my finger on my friend's little brother's serated knife earlier today......